Where to plug in H100 fan controller fan cable lead?

Hi guys,

It's my first pc build ever. I've just finished installing the h100 and have one small question. See following image first.

http://imgur.com/neK3X

The h100 fan controller has two leads - one for power and the other, a smaller one, presumably for fan voltage control but regarding the small fan voltage cable on the right:

1) Where do I plug it in? I was thinking I could hook it up to the 650d front io panel fan controller. Is that a bad idea? Or should it go on the motherboard and if so how am I supposed to connect up the power cable behind the case and the fan voltage cable on the MB given that the two are joint at the hip like siamese twins?

2) And what purpose does it serve? What is the intended use for such a cable? Surely the purpose of the h100 is to control four radiator fans. Why would anything else need to alter voltage to the controller?

Sorry for asking such n00b questions but I've never built a pc before. I've almost finished my first build. Just have to cable tidy the back and plug in memory and two gpus and I'm done. Will post pictures here (on separate thread) once done.

Thanks.

I found the answer to both my questions at:

http://www.corsair.com/en/blog/installing-the-hydro-series-h100-extreme-performance-cpu-cooler-in-the-obsidian-800d

The answers:

The final step is to plug in the power cable for the pump. The power cable for the pump has two connectors, one will plug directly into your PSUs 4-pin peripheral cable, and the other will plug directly into your motherboards CPU 4-pin fan header. The H100 is powered by the 4-pin peripheral cable, while the 3-pin fan header sends pump RPM information to your motherboards BIOS.